The hybrid fiber-coaxial (HFC) cable plant delivers cable services to subscribers using a complex network that includes active and passive components. The HFC network is a broadband network that combines optical fiber and coaxial cable. The optical fiber segment connects a headend to fiber nodes using a length of optical fiber from the headend to each fiber node. The coaxial segment connects each fiber node to approximately 25 to 2000 customer locations using coaxial cable, amplifiers, line extenders, and taps.
Equipment in the HFC cable plant periodically measures the radio frequency (RF) performance of the components of the HFC network using a variety of RF metrics, such as receive power level, signal-to-noise ratio (SNR), and codeword error rate (CER). Degradation in the RF metrics indicates degradation in quality of service to customers, manifesting either as a degradation in network performance, or in extreme cases, as a service outage.